We shall determine whether unsaturated lipids subjected to mild air oxidaion, autoxidation, photooxidation, or enzyme oxidation become mutagenic towards test strains of Salmonella typhimurium. Unsaturated lipids have not heretofore been viewed as potential sources of mutagens, but as air oxidation of polycyclic aromatic hydrocarbons and of cholesterol yield mutagenic species, it seems possible that unsaturated lipids might respond similarly. Unsaturated fatty acids, triacyglycerols, and phospholipids will be oxidized by mild oxidants, their oxidation products tested for mutagenicity, and any mutagens detected isolated and identified using high performance liquid chromatography, mass spectrometry, etc.